1. Field of the Invention
This invention relates to a dust control system for controlling dust generated by the operation by a mining machine, and more particularly to a transition section for connecting a pivoting joint between two sections of the duct system used to convey the dust away from the cutting head of a continuous mining machine.
2. DESCRIPTION OF THE PRIOR ART
This invention is especially concerned with the problem of removing dust from the air in a mine in the vicinity of equipment which, in use in the mine, generates dust. It is particularly concerned with removal of dust from the air in the vicinity of the mine face caused by the cutter head of a continuous coal mining machine. The general description of such a dust control system and of a typical coal continuous mining machine is disclosed in U.S. Pat. No. 4,380,353 which disclosure is incorporated herein by reference.
The dust control system as described in U.S. Pat. No. 4,380,353 while in general functioning adequately has had assembly and operational problems in the area of the connection between the duct section mounted on the boom of the vehicle, which boom swings upwardly and downwardly, and the fixed duct section which is mounted on the vehicle body. The disadvantages of the prior art transition sections are that a great deal of turbulence within the duct section is created because of the shape of the prior art transition sections. This can be seen in FIG. 13 of U.S. Pat. No. 4,380,353 wherein the area 95 and 105 the transition duct section is not smooth. In addition air leakage out of the duct system at the transition section was higher than desired with the concomitant loss of dust prior to the downstream scrubbing system.
Also fabrication and assembly of the prior art duct systems was much more difficult and costly than the transition section of the current invention since sliding telescoping ducts require tight dimensions in order to facilitate sealing while permitting ease of sliding. Also installation and maintenance of the prior art transition section was exceedingly difficult since the transition duct had to be installed integrally with the intake duct mounted on the boom and then assembled into the fixed dust transition. Replacement of the duct section because of the tight tolerances is difficult.
In the transition section of the present invention relatively loose tolerances can be maintained especially in the top and bottom portions of the transition section. The side portions must be maintained within reasonably close tolerances to prevent loss of dust laden air around the sides of the fixed duct at the end of the vehicle adjacent the boom. In order to perform maintenance on the duct design of the present invention all that is necessary is to remove two hinge pins and replace either of the only two parts which may have become worn or damaged.
There are other mining machines of the continuous mining type which disclose duct sections mounted thereon however no transition section of the type disclosed herein is taught or suggested. Such a machine is shown in U.S. Pat. Nos. 4,289,509, 3,743,356 and 4,076,315.
U.S. Pat. No. 3,810,677 discloses a dust collection system having a flexible duct arrangement rather than a duct arrangement having rigid rectangular cross section.
U.S. Pat. No. 3,258,848 discloses a transition section for air drying machine which applicant does not believe is analogous art to the mining machine and which in any event does not teach or suggest a transition section of the present invention.